X-ray apparatus



"Jan, 10, 1928. 1,655,636

If. s. SMITH X-RAY APPARATUS Filed Dec. 8. 1926 l N VEN TOR.

. ATTORNEY.

Patented Jan. 10, 192 s.

nnrrso ;STATES- PATENT, QFFICE.

FRANKLIN S. SMITH, OF BROOKLYN, NEVT YORK, ASS IGNORTQ PRGDUCTS PROTEC TION CORPORATION, A CORPORATION OF DELAVVAEE. i

X-RAY APPARATUS.

Application filed December This invention relates to X-ray apparatus and systems. g

One of the objects of this invention is to provide an X-ray apparatus and system which will be of highly effective actionwhen in use and yet capable of simple and inexpensive construction. Another object is to provide apparatus of the above-mentioned character capable oi operation at relatively high voltages but in a manner thoroughly dependable and reliable. Another object is to provide an apparatus and system whereby, by the use of uni-lateral valves or rectifying devices and appropriate condensers, the lat ter may be appropriately charged from a source of relatively high alternating potential but without endangering the uni-lateral valves or rectifying devices. Other ob jectswill be in part obvious or in partpoint- 2 'ed out hereinatter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangen ients of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing there is shown in the single figure a diagrannnatic representation of the circuits and apparatus of a preferred embodiment of my invention Referring now to the drawing, there is shown at an X-ray tube having a cathode 11 conveniently of the filament type and an appropriate anode 12 for coaction therewith; the cathode 11 may be supplied with heating current through any appropriate source as, for :xample, by means of a suitable transformer indicated generally at 13. Two suitable condensers 14 and 15 are connected in series through a grounded conductor 16 and these condensers 14 and 15 are in turn connected by the conductors 17 and. 18 to the I cathode 11 and anode 12 respectively of the X-ray tube 10. 1t, therefore, each condenser is individually charged from an appropriate source, the potential applied to the unloaded X-ray tube 10 will be substantially the sum of the potentials across the charged condensers.

The condensers 14; and 15 are arranged to be successively charged from preferably the same source of potential, and the latter takes the term of a step-up transformer having aprimary winding 19 and a secondary wind- 8, 1926. Serial No. 153,282.

ing 20, one terminal of which is connected to the conductor 16 which connects the condensersl l and 15 in series; this terminal 01" the winding 20 may be grounded as at G. The transformer 19-20 of such ratio of transformation that the potential across the secondary winding 20 is appropriate for suitably c-hargii'ig each of the condensers 1.4. and 15; the primary winding 19 may be energized from any suitable source of alternating potential. t V n I l i The other terminal of the secondary winding 20 is connected to the movable blade member 21 ot a switchingdevice, the latter including the two fixed terminals 22 and 23 with which the blade member 21 may coactr The movable switch n'iember 21 is rotated by means of the synchronous motor 25, the latter being supplied with energy from the same source which energizes the primary winding 19 of the transformer 1920. The connection between the driving shaft of the motor 25 and the switch member 21is made through an appropriate insulating shaft26.

The fixed terminals 22 and 23 are spaced substantially 180 apart with respect-to the axis of rotation of the rotating switch blade 21, as will be clear from Figure 2. I

Terminal 22 is connected to the other ter minal oi the condenser 14: but through a rectifying valve such as a kenotron 27; the latter is provided with a cathode 28 in the form of a filament which may be heated from any suitable source such as a transformer 29. Conductor 30 connects the cathode 28 of the lrenotron 27 to the other terminal of the condenser 14. Conductor 31 connects the plate 32 ot' the'lrenotron 27 to the terminal 2201 the switching apparatus. 2

The other fixed terminal 23 of the switching apparatus is likewise connected through a rectifying valve but to the other side or terminal oi. the other condenser namely condenser 15. More specifically, conductor 33 connects the terminal 23 to the filament cathode 34 of the kenotron 85, the circuit being completed by conductor 36 leading from the one side of the condenser 15 t0 the plate or anode 37 of the rectifying valvej35. A suitable transformer 38 supplies heating current to the filament 3 The blade 21 is preferably of such a length that, when rotated, it clears the fixed terminals 22 and 23 which, in view of the high potentials in the circuit it need not contact;

be clear from the direction of the and the rotatable .switch member an, being driven at a synchronous speed, is so positioned that, when the peak of that halt-cycle of the potential of the secondary winding 20 of the transformer 19-2O occurs and which the uni-lateral action of the lrenotron 27 will permit to pass therethrough, the switch blade 2% will be in the position substantially as shown in the drawing. During this interval, the condenser 14: will be charged uni-directionally and only during that particular half-cycle; tne corresponding charging circuit will be seen to include the secondary winding 20, conductor 16, condenser 1- conductor 30, cathode 28 and anode 32 of the kenotron 2'7, conductor 31, switch terminal 22, switch blade 21, and thence to the other terminal of the secondary winding 20. The charging current, thus i flowing to the condenser 1 i, tiows through the charging circuit in the direction in which the latter has just been traced, as will electron flow, in the valve 27, from the cathode 28 to the anode 32 thereot; according y, the electron {low of charging current through the condenser 14 will be seen to be in the direction from right to left as the diagram of the figure is viewed in the drawing.

By the time the switch blade 21 has moved 180 so as to be positioned in circuit-closing relation with respect to the fixed terminal 28, the other halt-cycle of the potential of the secondary winding 20 will be occurring and the condenser 15 charged thereby, the latter will take place through a circuit which will be seen to include the secondary winding 20, switch blade 21, fixed terminal 23, conductor 33, cathode 3' and anode 37 of the kenotron S5, conductor 86, condenser 15 an7 thence back to the secondary 20. The charging current thus flowing to the condenser 15 will be seen to flow about the charging circuit in the direction in which the charging circuit has just been traced, as will be clear from the fact that the electron liow in the unidirectional valve 35 takes place from the cathode 34 to the anode 37; accord ingly, the electron flow of charging current through the condenser 15 will be seen to be in the direction from the right to the left as the diagram of the figure is viewed in the drawing. But while the condenser 15 is thus being charged, and the switch blade 21. positioned in co-acting relation to the fixed terminal 23, there will have been interposed in the circuit of the kenotron 2? a gap equivalent to the spacing between the iincd ter-- minal 22 and the member 21 of the rotating" switch. More specifically, the gap thus interposed in the circuit of? the lrenotron. 27 will be equivalent to that illustratively shown in the drawing as between the member 21 and the fixed terminal 23.

The charging of the condenser 15 during ondary winding 20, would tnus bring about across the elements 28 and 21 a potential equivalent to the sum 0; the potentials of th charged condenser 1 1 and the developed end of the secondary vinding 20. This summation of potentials is one whichmay either cause. the over-stressing and resultant de.

struction of the lrenotron 27 or cause the maximum potential which the kenotron 27 can withstand to act as a limiting factor for thissunnnation of these voltages. But the inter-posing of the gap hereinbe'i'ore described between the anode 32 oi. the kenotron 27 and the associated terminal oi the secondary winding 20, greatly diminishes the possibility of overst-ressing the kcnotron 27 and the potential characteristics of the latter need not, therefore, act as limiting factors upon other parts of the system.

Both condensers 1% and 15 having become charged, a voltage equivalent to the sum ofthe potentials across the condensers becomes effective to excite the X-ray tube 10 in the usual way, whence the action hereinbetore described of successively charging the condensers 14c and 15 may be repeated.

It will be clear -from what has been set forth hercinabove that, the electron [low oi charging current through the condensers 1 1: and 15 being in the same direction (that is, in the direction from the right to the left as viewed in the drawing), the electron flow of discharge current from the serially con.- ncctcd condensers 1d: and 15 will be in the reverse direction (that is, in the direction from the left to the right as viewed in the drawing) so that the electron flow of ciP-" nj. which energizes the lion) lube ll) will tube place in the following circuit and in the (Ii-- rectiou in which the latter is traced: Oil-- dcnscrs lat -15, conductor 17, cathode 11 ot the X-ray tube 10, anode 12- ot the Iii-ray tube 10, and conductor 18, the latter, in be ing connected to the one terminal oi the serially connected condensers 14-l5, coinpleting the circuit. This flow o'l energizing current will thus be seen to be in the (itrection oi the electron flow within the X-ray tube 10, namely, in the direction from the cathode 11 to the anode The X-ray tube 10 will thus be seen to be energized. unidirectionally. it being noted that the condensers 14: and 1.5, individually charged successive halt-waves, are always charged in the same direction, the latter action )eing assured by the respective reclill ll ill) tying valves as well as by the synchronously operated switching device. It will be further understood that the successive chargii'ig of the condensers l l and 15, each being operated during one-halt cycle of the alternating potential of the transformer 19-2tl, takes place at substantially great rapidity, as will be further clear if it be assumed that the transformer primary 19 be supplied trom a usual commercial source ot alternat ing potential, such as a sixty cycle source, for example. The ei'lect or such substantially rapid successivecharging or the con.- densers l t and 15 substantially suchas will maintain across the conductors l? and 18, and hence across the electrodes of the X-ray tube 10, a substantia 1y continuous unidirectional potential equivalent approxin'iately to twice the potential. of the higlr tension winding 20 of the transformer l920; this unidirectional potential, due in )art to this eiiect. is substantially free from material variations or pulsations, due further to the inherent action or the condensers in tending to smooth out what would otherwise be substantial pulsations.

it will thus be seen that the mechanical features of the synchronously operated mechanism act to protect the one kenotron associated with one condenser as by interposing an appropriate gap in the circuit thereof while at the same time they so affect the circuit of the other lrenotron associated with the other condenser as to permit the cl'iarging ot' the latter in its associated circuit to take place.

It will. furthermore be seen that there has been provided in this invention an X-ray apparatus and system capable of simple and inexpensive embodiment in practical form, and perfected to make possible the supply of inn-directional energy to the X-ray tube but from an alternating source of potential of about one-half the magnitude of that which ultimately excites the X-ray tube, all without endangering associated parts of the apparatus.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbetore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

it claim as my invention:

1. In apparatus of the character described, in combination, an X-ray tube; a pair of condensers connected serially and bridged across the said X-ray tube; and a charging circuit for said condensers comprising a source of relatively high alternating potential and a uni-lateral valve arranged'in series with each of said condensers, and a synchronously driven switching mechanism adapted to close one condenser-charging circuit and to interpose a gap in the other condenser-charging circuit. 7

2. In apparatus of the cha 'acter described, in combination, an X-ray tube; a pair otl condensers connected serially and bridged across the said X-ray tube; and a charging circuit for said condensers comprising. a source of alternating relatively high potential, one terminal of which is connected between said serially connected condensers, a uni-lateral valve connected between the other terminal of said source of high potential and the other side of each of said condensers, and a synchronously driven mechanism for closing one condenser -charging circuit through one valve and to interpose a vgap between the alve in the other condensen charging circuit and the said source of high potential.

3. In apparatus of the character described, in combination, an X-ray tube; a pair of condensers serially connected and adapted to supply energy to said X-ray tube; and means for charging said condensers individually, said means including a transform or, a rectifying valve connected between each condenserand said transformer for uni laterally charging each condenser from said transforn'ier, and a synchronously driven switch for controlling each condensercharging circuit and adapted to permit one condenser to receive a charge during one half cycle of the alternating potential of said transformer and to permitthe other condenser to receive a charge during the next half cycle.

4:. In apparatus of the character described, in combination, an X-ray tube; a pair of condensers connected serially and bridged across the said X-ray tube; and a charging circuit for said condensers comprising a relatively high potential transformer winding having one terminal connected between said serially connected condensers and having its other terminal connected to the movable member of a synchronously driven switching apparatus, the latter having two relatively fixed terminals each of which is connected to the other side of one of said con densers through a uni-lateral valve.

5. In apparatus of the character described, in combination, a pair of condensers serially connected, a source of alternating relatively high potential having one terminal connected between said serially connected condensers, a kenotron having its cathode connected to the other terminal of one condenser, a kenotron having its anode connected to the other terminal of the other condenser, and means synchronously operative for electrically connecting the other terminal of said source of potential to the anode of said firstinentioned kenotron and for interposing between the other terminal of said source of ion high potential and the cathode or" said sec end-mentioned kenotron a safety gap.

6. In apparatus out the character described, in combination, a pair of condensers serially connected, it sonrce of alternating relatively high potential havi g one terminal connected between said sei ally connected condensers, a kenotron having its cathode connected to the other triuinal of one condenser, a kenotron having its anode connected to the other terminal or the other condenser, a gap electrode connected to the anode of said firstn'ientioned lcenotron, a gap electrode connected to the other terminal of said source of high potential and spaced from said firstnientioned gap electrode, a gap electrode connected to the cathode of said second mentioned henotron and spaced from said second-mentioned gap electrode, and means eer-mac synchronously ell'ective for successively and substantially closing the gaps between said second-mentioned gap electrode and the remaining gap electrodes.

7. In apparatus of the character described, in combination an Xa'ay tube; means forming a capacity and adapted upon being charged to supply, on discharge, energy to said X-ray tube; and means for charging said capacity means, said means including a source oi? alternating relatively high potential, a kenotrou and a high tension gap, connected serially with said capacity means, and synchronously etl'ective means for substantially closing said gap.

In testimony whereof, I have signed my nznne to this specification this 4th day oi December, 1926.

FRANKLIN S. SMITH. 

